The present invention relates to magnetic bearing devices for rotating a rotary body as magnetically supported by magnetic bearings without contact.
Magnetic bearing devices, for example, for use in turbo molecular pumps of the magnetic bearing type comprise a machine main body having position sensors for detecting the position of a rotary body and magnetic bearings for magnetically contactlessly supporting the rotary body, and control means for controlling the magnetic bearings based on the signals from the position sensors. While many magnet bearing devices produced by a certain manufacturer are used by users at widely separated locations, the bearing devices are independent of one another and are conventionally controlled and maintained individually. Accordingly, the magnetic bearing device can not be checked for operating state or for the diagnosis of failure at a place other than the actual location of the device (the site of installation of the device for the user). Although the device as installed requires periodic maintenance, the manufacturer is unable to recognize or grasp the operating state of the device as stated above, so that every time need arises, the manufacturer must dispatch the technician to the site for him to grasp the operating state or to diagnose failure and to thereafter adjust the control means. Since such work at the installation site must be performed for each of the magnetic bearing devices of the users at various remote locations, there is the problem that the work requires much time and labor. Further the control circuits of the control means of magnetic bearing devices comprise an analog circuit and digital circuit. In the case of either circuit, a need is likely to arise to improve or alter the magnetic bearing control characteristics during use. In such an instance, the manufacturer must dispatch the technician to the site for the adjustment of the control circuit as in the above case.